<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      background-color: black;
    }

    h1 {
      text-align: center;
      /* text-shadow: 2px 2px 0px red; */
      /* text-shadow: 2px 2px 3px red; */
      /* text-shadow: -2px -2px 0px red; */
      /* text-shadow: -2px -2px 0px red, 2px 2px 0px blue, 5px 5px 0px yellow; */
      text-shadow: 0px 0px 5px yellow;
    }
  </style>
</head>

<body>

  <h1>文</h1>
  <!-- <h1>文字阴影</h1> -->
</body>

</html>